Castrol Syntec - mileage recommendation in high heat highway travel?

[ragtophardtop]

This is my first time using castrol. I put 10w30 into my FJ cruiser and took a 4000 mile roadtrip, where 2 six hour highway sessions were between 110 and 115 degrees F. I'm about to take another 3000 mile roadtrip, again almost all highway miles.

Do highway miles otherwise damage the oil at these temps? I'd like to hold off on the next oil change until I get back, which I would normally do with a decent quality synthetic, but this is my first experience in such high heat.

 

[Barkleymut]

What did your heat needle say? The engine did not even notice it was 110 degrees.

 

[Accent Abuser]

This is my first time using castrol. I put 10w30 into my FJ cruiser and took a 4000 mile roadtrip, where 2 six hour highway sessions were between 110 and 115 degrees F. I'm about to take another 3000 mile roadtrip, again almost all highway miles.

Do highway miles otherwise damage the oil at these temps? I'd like to hold off on the next oil change until I get back, which I would normally do with a decent quality synthetic, but this is my first experience in such high heat.

On the highway 7500 miles is fine. Lots of airflow across the engine and radiator. Stop and go city traffic and high temperatures is a different story, as the engine will sit there and heatsoak and you're constantly heating up the oil with acceleration.

 

[Hall]

7000 highway miles on a quality synthetic ? Piece of cake....

 

[Dennywires]

Probably 7500-10k

 

[pghvolvo]

Highway miles are equal to around 10% of city miles when it comes to engine wear. Highway miles are pretty gentle on engine oils. My owners manual for my Volvo says mainly highway driving, 10K miles or once a year OCI's. With urban driving they recommend 5K mile or every six month OCI's

 

[Obi Wan Noobi]

This is my first time using castrol. I put 10w30 into my FJ cruiser and took a 4000 mile roadtrip, where 2 six hour highway sessions were between 110 and 115 degrees F. I'm about to take another 3000 mile roadtrip, again almost all highway miles.

Do highway miles otherwise damage the oil at these temps? I'd like to hold off on the next oil change until I get back, which I would normally do with a decent quality synthetic, but this is my first experience in such high heat.

I would go for Mobil 1 FS 5W-40 for your application. It's cheap, available everywhere, very good oil. There really isn't any good reason or use case left for 10W-30. It's about as pointless of a viscosity as 5W-20.

 

[SR5]

There really isn't any good reason or use case left for 10W-30. It's about as pointless of a viscosity as 5W-20.

I respectfully disagree. Most synthetic oils these days are Group III and the narrower the viscosity spread the less polymer VII (viscosity index improvers) required. So the oil will be more shear stable and have a lower Noack volatility. As long as you have the required cold starting ability.

A 10Wx oil is good down to 0F (-20C) so in a warm climate I would prefer a 10W30 over a 5W30, assuming similar base oil and add pack. Same for a 5W40, if a I don’t need the cold starting (5W) or the extra viscosity/HTHS for protection (40), then I would prefer a 10W30.

Sure if I’m the Mercedes Benz company selling cars around the world, then 0W40 covers cold starting in Alaska (0W) and high speed tracking on the Nurburgring (40). But most applications are more mundane than these extremes.

 

[Accent Abuser]

I would go for Mobil 1 FS 5W-40 for your application. It's cheap, available everywhere, very good oil. There really isn't any good reason or use case left for 10W-30. It's about as pointless of a viscosity as 5W-20.

More shear stable, which is important for longer drain intervals.

 

[ragtophardtop]

Thanks everyone for the info. I'm going to leave it in for the trip (running short on time anyway). By the time I'm back this oil will have 9k miles, and 7500 of those will be exclusively highway miles.

I am running 10w30 in the summer, but I probably should have been running 15w40. In the winter I may push it down to an easier starting viscosity in the winter as my car sees -30F temps. Previously it had gotten the dealer 0w20, which is not robust enough for this engine.

 

[Luftmasse]

I respectfully disagree. Most synthetic oils these days are Group III and the narrower the viscosity spread the less polymer VII (viscosity index improvers) required. So the oil will be more shear stable and have a lower Noack volatility. As long as you have the required cold starting ability.

A 10Wx oil is good down to 0F (-20C) so in a warm climate I would prefer a 10W30 over a 5W30, assuming similar base oil and add pack. Same for a 5W40, if a I don’t need the cold starting (5W) or the extra viscosity/HTHS for protection (40), then I would prefer a 10W30.

Sure if I’m the Mercedes Benz company selling cars around the world, then 0W40 covers cold starting in Alaska (0W) and high speed tracking on the Nurburgring (40). But most applications are more mundane than these extremes.

So a 5W40 wouldn't be ideal for higher operating temps vs 10W30? I figure the second number matters more than the winter rating.

 

[SR5]

So a 5W40 wouldn't be ideal for higher operating temps vs 10W30? I figure the second number matters more than the winter rating.

For higher operating temps, eg towing a heavy load up a mountain or racing etc, then yes I would definitely go a 40 grade. The winter rating now probably reflects the base oil group. A 0W40 is probably PAO (Group IV), 5W40 is probably Group III (including GTL), and 15W40 is probably Group II.

Given suitable winter starting, I would be happy with any of those above.

Now what about 10W40? Well if it’s a Group II 10W40 then I don’t want it, too high a Noack volatility and prone to shear. The older 10W40 conventional oils in particular were done poorly, lots of polymer viscosity index improvers (VII) that left deposits behind, hence GM saying not to use them, but a 10W30 was ok. This situation was improved when J300 starting giving minimum HTHS levels for viscosity grades, this effectively stopped the bad practice of making a 10W40 out of thin base stock and then jacking it up on plastic VII.

However if it’s a Group III and/or Group IV 10W40, then yes I want it a lot as it will be a very shear stable and low volatility oil

 

[Oliveoil2]

Probably 10-12k easy. Those 3.5l are very easy on oil.

 

[john_pifer]

Probably 10-12k easy. Those 3.5l are very easy on oil.

The FJ has the 4.0 (1GR-FE), and will run on anything.